1. Field of the Invention
The invention relates to a magnetic field array for measuring spatial components of a magnetic field.
2. Description of the Prior Art
It is generally known that in rpm and position sensors, for instance, such as are used for controlling motors or in transmission or vehicle dynamics controls in motor vehicles, a rotary motion or change of position is detected by means of a magnetic field variation that corresponds to the rotation or the change of position. Then as a rule, magnet sensors known per se are employed, which depending on the application and field of use may be Hall sensors or magnetoresistive sensors.
Besides magnetoresistive structures that are based on the anisotropic magnetic resistance effect (AMR), the more-sensitive giant magnetoresistance structures (GMRs) and tunnel magnetoresistance structures (TMRs) can be named in particular. The various magnetoresistive effects will hereinafter be summarized as XMR effects.
One disadvantage of the sensor arrays with the XMR effect is that in contrast to Hall sensors, they are sensitive to the magnetic flux density in the plane of the magnetoresistive film structures. Such magnetoresistive film structures are thin metal films which are applied to a substrate, in this case in particular a semiconductor chip. A semiconductor chip is preferentially used because it has good substrate properties and because electrical connections or all of the signal processing can be integrated with it.
However, for certain applications, magnetic field measurements in three directions in space are required, in which besides the information about the magnetic flux density in the semiconductor chip plane, information about the component perpendicular to that is required as well.
It is known for instance from European Patent Disclosure EP 1 436 849 B1 that in conventional Hall sensors, which typically measure the magnetic flux density perpendicular to the chip plane, the possibility exists of determining the missing components in the chip plane by means of special vertical Hall elements with lesser sensitivity.
From European Patent Disclosure EP 1 182 461 A2, it is known that in a Hall sensor, with the aid of a flux concentrator, the horizontal field components can be deflected into the vertical direction, so that then the magnetic field can be detected using a conventional Hall element.
However, if the greater magnetic field sensitivity of the magnetic field sensors is to be employed, utilizing the XMR effect, for direct determination of the vertical magnetic field component, then thus far in this respect it can be learned from European Patent Disclosure EP 1 860 451 A1 only that a projection of the vertical magnetic field component onto a beveled substrate face of the semiconductor chip can be detected, which means complicated production of the substrate with precise control of the substrate angle, so that then a conclusion can be drawn about the true vertical magnetic field component.